Telephone key with bisecting plate



Oct. 25, 19490 H. DORJEE TELEPHONE KEY WITH B ISECTING PLATE Filed Oct.24, 1946 /NVEN7UE HENDRIX 00.42/55 8r W W Patented Oct. 25, 1949TELEPHONE KEY WITH BISECTING PLATE Hendrik Dorjee, Eindhoven,Netherlands, as-

signor to Hartford National Bank and Trust Company, Hartford, Conn, astrustee Application October 24, 1946, Serial No. 705,340 In theNetherlands August 28, 1945 Section 1, Public Law 690, August 8, 1946Patent expires August 28, 1965 Claims. 1

This invention relates to a telephone key comprising a control-lever,which projects from the surface of attachment and is rotatable about aspindle supported by this surface, and atleast one set of springs whichis mounted on a mounting plate normal to the surface of attachment.

In the case of telephone keys of the conventional constructions, theframe consists of" an L-shaped metal strip, the two limbs of which formthe fastening and the mounting plate. This construction has theadvantage that the frame is extremely simple and is made in one piecewhich can be manufactured in a simple manner.

The object of the invention is to provide an entirely novel constructionfor a telephone key which has the aforesaid advantage of theconventional construction and in addition several further advantages.

According to the invention the frame of the telephone key is constitutedby a body of insulating material formed by the mounting surface, thefastening surface and a supporting surface which is normal to these twosurfaces and which establishes the mechanical junction between them, theparts of the set of springs be ing arranged on either side of thesupporting surface. About the spindle of the control lever this surfacehas a recess in which parts of the control lever are movable.

In this case the frame is made in one-piece constructed in such mannerthat it can be manufactured in series by a single operation so=that itis very cheap and on the other hand sumciently robust to satisfy therequirements in this respect. As may be seen hereinafter, moreover, theconstruction according to the invention enables various particularlyadvantageous forms of construction, owing to which the mounting issimplified and component parts are economized.

In order that the invention may be clearly understood and readilycarried into effect, it will now be described more fully with referenceto the accompanying drawing given by way of example.

Fig. 1 represents the frame which is used for the construction of thetelephone key according to the invention.

Fig. 2 represents one form of construction of the telephone keyaccording to the invention, in which use is made of the frame shown inFig. 1.

The frame shown in Fig. 1 consists of three surfaces I, 2 and 3substantially normal to one another. Surface l constitutes the fasteningsurface which serves to fasten the key to the wall of a cabinet or to achassis plate, from which the control lever 4 (Fig. 2) projects. In theform of construction shown by way of example the attachment of thetelephone key to a wall is effected by means of metal tags 5 and 6. Asan alternative the attachment may be effected by means of screw boltsextending through apertures of the fastening surface I. The surface Ifurthermore comprises the bearings for the spindle I of the controllever 4.

As may be seen from Fig. 2, the mounting surface 2 has piled on it twosets of springs 8 and 9. The springs are insulated from one another bymeans of plates IU of insulating material, the sets being clampedtogether by metal end plates II and I2. The plates H and I2 areinterconnected by screw bolts l3 and M which are passed throughapertures 15 and I6 (Fig. 1) in the surface 2. The mounting surface 2and the sets of springs attached thereto are supported by the third ofthe three surfaces which are normal relatively to one another, 1. e. thesupporting surface 3 which establishes the mechanical junction betweenthe mounting surface 2 and the fastening surface I. Each set of springscomprises two piles of spring arranged on either side of the supportingsurface 3. This surface bisects the key so to say, so that the parts ofthe surfaces I and 2 projecting on either side have only half the totalwidth of these surfaces. The compact construction thus ensured permits,in spite of the use of insulating material instead of metal, to fulfilthe mechanical requirements. In this case it is essential that thesupporting surface 3 about the spindle l of the control lever t exhibitsa recess (in the case represented a semicircular recess) in which partsof the lever 4 are movable which will be described in detailhereinafter.

The frame construction described permits to economize in price andweight by the use of insulating material and in addition to obtaindiverse constructional advantages. The mounting surface, in effect, isprovided on the rear with a dovetail profilation. The insulating platesl0 and the compression plates H and I2 of the sets of springs exhibit arecess fitting this profile, so

3 that they are supported in a lateral direction i. e. against movementsin their plane, which considerably facilitates th mounting (thestacking).

The control lever is provided on either side with a roller l8 whichdrives the usually central springs 19 and 20 of the sets. These springsare required to be at rest in the mid-position (not shown). This isensured most easily by arranging the mounting surface 2 mid-way thekey 1. e. in such manner that the Spindle i of the lever 4 is in linewith the mounting surface, the springs l9 and 23 being symmetricallymounted on either side of this surface. If the mould is given a suitableconstruction the mountin surface is automatically at the correct height.

The movement of the Springs is and 20 is transmitted by ladder-shapedmembers 2| and 22 to the other driven springs of the sets. The

surface 3 is provided on either side with profiled slits, in whichstrips 23 and 2d are secured by gluing. These strips are made ofinsulating material and provided with perforations which are chosen inaccordance with the set of springs to be used. The stationary springs ofeach set have a lateral projecting part by means of which they rest,under the desired preliminary tension, in one of the recesses 25 ofstrips 23 and 24. In order to minimize the number of component parts,the non-driven springs of the set are provided on either side with aprojecting part, so that they can serve both on the right hand side andon the left hand side. The centre of the frame exhibits, along the lineof intersection of the surfaces 2 and 3, a bore 26, which accommodates ascrew spring which urges a steel ball against the cylindrical surface ofthe member 2? of the control lever 4. In the mid-position of the lever 4this ball drops precisely into the stop slit 28 provided in the saidmember. In this manner the control lever is blocked in the mid-position.

What I claim is:

1. An electrical contact device comprising an electrically insulatingwall portion provided with a recess at one end thereof and having asurface thereof lying in a given plane, an electrically insulatingfastening portion provided with an aperture, said fastening portionhaving the major surface thereof lying in a plane substantiallyperpendicular to said first plane and being integral to said wallportion, an electrically insulating mounting portion integral to saidwall portion and having a mounting surface thereof lying in a planesubstantially perpendicular to the planes of said wall portion and saidfastening portion, a spring-contact assembly secured to said mountingportion and having a portion thereof positioned adjacent to saidsupporting portion and extending towards said fastening portion, and arotatable member pivotally secured within the aperture of said fasteningportion and extending into said recess portion.

2. An electrical contact device comprising an electrically insulatingWall portion provided with a recess at one end thereof and having asurface thereof lying in a given plane, an electrically insulatingfastening portion provided with an aperture, said fastening portionhaving the major surface thereof lying in a plane substantiallyperpendicular to said first plane and being integral to said wallportion, an electrically insulating mounting portion integral to saidwall portionand having a mounting surface thereof lying in a planesubstantially perpendicular to the planes of said wall portion and saidfastening portion, said supporting portion substantially bisecting thesaid mounting surface, a spring-contact assembly secured to saidmounting portion and having a portion thereof positioned adjacent tosaid supporting portion and extending towards said fastening portion,and a rotatable member pivotaily secured within the aperture of saidfastening portion and extending into said recess portion.

3. An electrical contact device comprising an electrically insulatingwall portion provided with a recess at one end thereof and having asurface thereof lying in a given plane, an electrically insulatingfastening portion provided with an aperture, said fastening portionhaving the major surface thereof lying in a plane substantiallyperpendicular to said first plane and being integral to said wallportion, an electrically insulating mounting portion integral to saidwall portion and having a mounting surface thereof lying in a planesubstantially perpendicular to the planes of said wall portion and saidfastening portion, said supporting portion substantially bisecting thesaid mounting surface, spring-contact assemblies respectively secured tosaid mounting portion and having portions thereof positioned adjacent tosaid supporting portion and extending towards said fastening portion,and a rotatable member pivotally secured within the aperture of saidfastening portion and extending into said recess portion.

4. An electrical contact device comprising an electrically insulatingwall portion provided with a recess at one end thereof and having asurface thereof lying in a given plane, an electrically insulatingfastening portion provided with an aperture, said fastening portionhaving the major surface thereof lying in a plane substantiallyperpendicular to said first plane and being integral to said wallportion, an electrically insulating mounting portion integral to saidWall portion and having a mounting surface thereof lying in a planesubstantially perpendicular to the planes of said wall portion and saidfastening portion, said supporting substantially bisecting the saidmounting surface, spring-contact assem blies respectively secured to thebisected portions of the said mounting portion and having portionsthereof positioned adjacent to said supporting portion'and extendingtowards said fastening portion, and a rotatable member pivotally securedwithin the aperture of said fastening portion and extending into saidrecess portion.

5. An electrical contact device comprising an electrically insulatingwall portion provided with a recess at one end thereof and having arecessed surface thereof lying in a given plane, an insulatingelectrically fastening portion provided with an aperture, said fasteningportion having the major surface thereof lying in a plane substantiallyperpendicular to said first plane and being integral to said wallportion, an electrically insulating mounting portion integral to saidwall portion and having a mounting surface thereof lying in a planesubstantially perpendicular to the planes of said wall portion and saidfastening portion, a spring-contact assembly secured to said mountingportion and having a portion thereof positioned adjacent to saidsupporting portionand extending towards said fastening portion, and arotatable member pivotally secured within the aperture of said fasteningportion and extending into said recess portion, certain spring portionsof the'said assembly being provided with projections extending into thesaid recessed sur- UNITED STATES PATENTS face Of the Wan portion. NumberN mt HENDRIK DORJEE- 836,067 Dean Nov. 13, 1906 918,682 Leich Apr. 20,1909 REFERENCES CITED 1,109,919 Gilson Sept. 8, 1914 The followingreferences are of record in the 1,333,117 Klay Mar. 9, 1920 file Of thispatent: 1,763,006 Murphy June 10, 1930

